engleski

Paraoxonase-1 activity in horses infected with Leptospira spp.

Leptospirosis is a serious zoonotic infectious disease of humans, domestic animals and wildlife with worldwide distribution. It is considered to be a toxin-mediated disease where several endotoxins such as lypopolysaccaride (LPS), glycolypoprotein, sphingomyelinases and phospholipase C play a role in the cytotoxicity and apoptosis of lymphocytes and other cells. In addition, they stimulate adherence of neutrophils to endothelial cells and platelets leading to inflammation and lipid peroxidation. Considering the anti-inflammatory and anti-oxidative properties of paraoxonase-1 (PON1) the aim of the study was to investigate the effect of infection with Leptospira spp. on PON1 activity and lipid status in horses. A total of 63 sport and leisure horses’ sera were chosen among those routinely serologically examined on leptospirosis during the year 2009 in Croatia. Serum samples were tested by microscopic agglutination test (MAT) using 12 serovars in the antigen panel. Sera included in the study were divided into three groups according to the estimated level of antibody titre against Leptospira spp. Out of 63 sera, 21 were chosen as serologically negative on leptospirosis (antibody titre < 50) (group 1), 23 had residual or anamnestic antibody titre (50-200) but not excluded possible carriers of Leptospira (group 2), and 19 had high antibody titre (>1600) indicating recent Leptospira infection (group 3). PON1 activity and lipid status (triglyceride, total cholesterol and HDL-cholesterol concentrations) were measured in the sera on the Olympus AU-600 automatic analyzer (Olympus Mishima Co., Ltd., Shizuoka, Japan). PON1 activity was measured spectrophotometrically with paraoxon as a substrate while lipid status parameters were determined using standard commercial kits (Olympus Diagnostica GmbH, Hamburg, Germany). Serum PON1 activity was not significantly different between investigated groups (304 U/L, 301 U/L and 334 U/L, respectively ; p>0.05). Lipid status was not significantly different among study groups as well. There was no difference in PON1/HDL ratio between three groups (203 U/mmol, 203 U/mmol, 235 U/mmol, respectively ; p>0.05). However, significant positive correlations of PON1 with total cholesterol (r=0.424 ; p<0.001) and HDL-C (r=0.316 ; p<0.05) were found for all samples. These preliminary results showed that PON1 is probably not involved in the pathogenesis of inflammation related to leptospirosis in horses, but that hypothesis has to be elucidating in further studies.

leptospirosis; horses; paraoxonase-1; oxidative stress; inflammation

nije evidentirano